Deciphering Bill Cipher
by Silver-PenofTime
Summary: When Katie finds a triangle laying on the road on her walk home from work in Gravity Falls, she rescues it. Now she's stuck with the most annoying thing she has ever encountered. Bill isn't the only creature pestering her. Something else has taken notice, and is creeping in the night to fulfill its own purpose.
1. Chapter 1

**Hey guys. For anyone who was reading this, I found a direction and have deleted everything of the old one. I don't like writing without a direction, so here goes!**

**Silver**

**Chapter One: Triangles**

It wasn't unusual for Katie to come home late on a Friday night. She wasn't drunk or out partying, oh no. She was at work, folding pitas and cooking pizzas at the little Greek restaurant she worked at. She worked late, so showing up at 11 at night, tired and smelling heavily of bread and hummus, was hardly out of place. However, something was certainly out of place tonight. Her two room mates, Jo and Shea, exchanged glances when she walked in.

"Katie...what is that thing you're carrying?" Shea asked, straining herself off the couch to get a better view of the thing cradled in her arms.

"I'm not exactly sure." Katie walked in and laid the thing in her arms gently on the wooden coffee table. Both young women gasped in surprise.

It was...a triangle? A gently glowing yellow triangle that was about a foot on each side. It looked like it was made of some type of brick or stone. It had a large eye in its center that was closed, and a black bowtie hung below the eye. A small top hat and cane were laid next to the creature. All three women stared at it in silence for a minute before Jo spoke in a whisper.

"Katie what the fuck?"

"Look, I saw it lying kind of out of the way when I was walking home. I took the back way, you know, the shortcut around the back of the psychology lab and up around that old computer place? I found it lying outside there. I don't know what it is but I couldn't just leave it there!" Katie tried to defend herself.

"Yeah, you totally could have. Katie, that friend of yours that told us about this place _warned us _about shit like this," Jo waved her arms over the creature, "He said Gravity Falls was a weird town!"

"I know he did, but he never mentioned magic triangles!"

The three continued to argue, not noticing the creature stirring until it shot into the air, cackling.

"Well that was unexpected! I didn't expect him to come after me like this! Hahahaha!" It spoke in a strange, almost metallic voice that range loudly in the small apartment. It hovered over their heads and waved a hang, hat floating onto its head and cane grasped firmly in a small hang. It began twirling the cane as it looked over the three stunned fleshsacks gawking up at it.

"Thanks for helping me out there, you got me out of a real scrape. I'm lucky you moved me before he came back for me. Can't believe that boner was so bold. Anyway, the name's Bill Cipher!" He turned to look down at the one who had rescued him. She was in her early twenties, wearing a black uniform, with short brown hair and tired gray eyes. She wasn't anything special in appearances, but who was in the eye of a omnipresent dream demon? The fact that she had helped him at all was enough to catch his interest.

"Uhm...I'm Katie, these are my room mates Jo and Shea."

Bill gave a cursory glance to the other two. Jo was shorter and more compact, with brown hair and broad shoulders. Shea was taller and lankier, with bright blue eyes and a smile that came from several well-crafted puns. He shrugged and returned his attention to Katie.

"Okay. Look, I'm a little busy at the moment. I've got things to work on and I can't do them here. So take this." Bill waved his hand and a card appeared. He held the paper out to Katie, who took it curiously. Like her friend who had lived here for a few years before he moved to learn more from schools in Europe, she had a deep curiosity for the...unexplained. The card simply had a triangle with an eye in the middle on it in yellow ink, shining against the black paper.

"What is this thing?" She asked.

"Heh heh. I thought you were smart, Pita girl. It's a card. Think of it as an I.O.U. I'll show up once I get things settled and I can figure out how to repay you. You got me out of a real scrape. Remember, nothing is what it seems around here ladies! Bye!" With a flash of light Bill was gone.

Katie sat in the armchair across from the couch in their living room and gazed intently at the card. She wasn't sure what she had just gotten into. When she had told her two friends about the open space in the town her friend had been talking about for years, they had heartily agreed. They all attended graduate school at the university close the apartment, though the place was tiny. She hadn't expected this. She would have to write to her friend to see if he had any knowledge of a creature going by the name Bill Cipher.

"Ugh. I need a drink. A stiff drink."


	2. Chapter 2

**Chapter Two: Less of a Triangle?**

Nothing really changed for Katie or her room mates for the first few weeks after their strange encounter with Bill. Shea continued her research on oysters and pea crab parasitism. Jo continued taking classes to help her on her way to becoming an elementary school science teacher. And Katie continued juggling her job at the Greek restaurant, work in the psychology lab, and research with one of the college's history professors. All three of the young women found themselves very busy; but only one of them felt as if they were being watched as they worked. Only one felt the burning of a single eye searing into them as they typed, read, cooked, watched tv, fed the snake, fed the gecko, fed the fish, ate, washed dishes, everything!

Katie grunted and looked up from the paper on her desk for maybe the hundredth time. She couldn't shake the feeling off. She knew she was being watched and she knew who was behind it. She couldn't see him or anything, but she could feel his presence. It bothered her, and it drove her mad that she couldn't yell at him to go away. She hadn't heard back from her friend since she had written him about the issue a few weeks ago. It would probably be a couple of months before she got a return letter, probably wordy and warning her to avoid anything that had to do with a certain triangle.

Said triangle was hovering in the mindscape a few feet away from the tired looking young woman. Bill had finished his business a week ago, and had devoted his time to watching this person before he decided to try to repay her. He needed to make sure he wasn't helping _just any_ human, after all. What a waste that would be. Learning that she was pen pals with Pine Tree had been amusing. He would have to intercept and destroy his return letter if his forming plan was to work.

His eye narrowed a bit as the girl yawned and pulled her signature blue, cat-eared hat off and tossed it to the foot of her bed. She was going to bed soon. Bill would have to leave before she entered the dreamscape. He was not interested in dealing with the dreams of a stressed 21 year old. He had seen enough "Oh no I'm late to class" and "Oh God I'm naked in public" dreams to last him an eternity. Which he had. Plus, she could potentially see him once she fell asleep, and that was no fun at all.

Bill had plans for this woman. She was just as curious about the supernatural as Pine Tree had been, and even less cautious. She spent a lot of her limited free time investigating codes and hunting for folklore She didn't know what Bill was, which gave him an advantage. It had been several years since he had made an attempt at conquering the "real" dimension. He had to admit that he wasn't going anywhere without a trusting assistant. He had had one, ages ago, but that had crumpled. He would be more careful with crafting and shaping this disciple. Had he a mouth, he would have grinned. Yes, that was a perfectly juicy idea. Brilliant!

He chuckled to himself and vanished deeper into the mindscape. He would begin immediately. He flew off in the direction of a particularly dilapidated old building on the outskirts of Gravity Falls. It was time to attain a new, more solid form.

**A week long time skip. Because transitions are not my strong point and my snake is begging like a dog to share my dinner. You cant have pasta, Romulus!**

Katie returned home fairly early. It was unusual, but she had finished most of her work pretty quickly today. She wasn't on the schedule today, which gave her time to finish a book on Alchemical history for her professor. Maybe she could even relax and watch tv afterward, or take a relaxing bath. She shrugged. She would figure out what to do after she finished the book.

She flopped onto the couch and propped her feet up on the coffee table after kicking off her shoes and launching them across the room. She would move them later. Maybe. She grabbed her book and started reading. Time seemed to pass pretty quickly. Within an hour she had finished the last chapter. She grinned and shut the book.

"Good, good, good. I can email him later to ask what he needs me to do now." She stood and looked around the apartment. Neither of her room mates was home at the moment. Jo was probably in class, or at the grocery store. She loved to cook, and was the best at it in the apartment. Her goulash was to die for, and she made a wonderful tuna casserole. Shea was undoubtedly at the bio lab shelling and weighing oysters, and collecting the tiny parasitic pea crabs she found in them. She wouldn't be home until early in the morning, as she collected oysters to process at about a hundred per trip. Katie had gone with her once, slogging through mud and algae-filled water, carrying a large bucket to hold all of the bivalves. She never wanted to see another damn oyster ever again.

A knock at the door startled her. No one ever visited them, unless it was the maintenance people coming to fix something. She didn't think anything in the apartment was broken. She curiously opened the door, ready to send whoever it was away so she could relax.

A man a good deal taller than her met her eyes. He was lean and lanky, with legs that seemed to go on for miles and a confident air about him. One of his golden-hued eyes was hidden under a black eyepatch, a familiar yellow triangle stitched into the fabric. A tall top hat sat on the mass of blonde hair atop his head, and he work black pants, a white button up shirt, and a long yellow tail coat, with a black bowtie clinging to his neck. He grinned widely at her when recognition, followed by annoyance, flashed across her face.

"Hey there Ears. It's been awhile." Bill Cipher almost cooed at her.

Katie groaned in exasperation. She wasn't going to be relaxing anytime soon.


	3. Chapter 3

**Chapter Three: First Deals**

Shea and Jo shifted awkwardly on the couch, Bill seated cheerfully between them draining a bottle of Katie's vodka and gnawing on an uncooked chicken thigh; he didn't seem to understand the concept of food poisoning quite yet. Katie herself was seated on the floor near them, watching the dream demon down half her bottle of expensive alcohol. It was the day after Bill had showed up at their door, and he had made it very clear that he wasn't leaving. He hadn't really said what he wanted, just that he was sticking around. After deciding that it was best not to bicker with a creature they didn't know about, the three agreed that he could stay and sleep on their couch.

"Oh man this alcohol is good stuff!" Bill crowed happily.

"Yeah, and it's expensive, so don't drink all of it. I don't get another paycheck until next week and I need to buy more mice for Romulus." Katie muttered tiredly.

"Awww, don't be such a grump!" Bill giggled and pinched her cheek, "I can help you get food to feed your snake, and some crickets for Octavian too!" He snapped his fingers and several live mice and crickets appeared out of nowhere and fell all over them. The three women screamed and jumped up to get away from the confused animals as Bill laughed with glee.

"Dammit Bill get rid of them!" Katie screeched.

"Sure thing, Ears." he snapped again and they were all gone. The three women calmed down and returned to their previous positions.

Bill grinned and relaxed. Yes, this was going to be perfect. He didn't care what Jo and Shea thought about him, though he should probably not push his boundaries too far. They could easily try to kick him out, and he would have to kill them, and Ears would be upset. If he was going to win her trust and get her to help him with the plan he was...still working on...then he would have to play nice.

"Sorry about that. It was too funny to resist." He apologized with a small smile.

"It's...fine. Just don't do it again." Katie offered, standing up and starting to pack her things into a backpack.

"Where ya going?" Jo asked nervously; it was obvious that without her there to disapprove of him, Bill would get bored and probably pull all sorts of tricks. He had already eaten one of the tv remotes, turned the gecko Octavian into a small dragon that had set the coffee table on fire and set off the fire alarm, and flooded the kitchen. They couldn't deal with that again.

"I'm going for a walk after I pack all of this stuff for tomorrow. Gotta go to the library to study for final exams." Katie sighed and stood up.

"Oh, one of us should go with you! It's dark out, it might not be safe! Bill, why don't you go and make sure she doesn't get jumped by muggers or something." Shea gave a hopeful smile; any respite from Bill's antics was a welcome one.

"Oh what a marvelous idea!" Bill grinned and dragged Katie outside by the arm, "Alright! Let's walk!"

Katie chuckled. She had known that Bill would follow her outside. He had been attempting to follow her everywhere; class, work, grocery store, you name it. She had seen how frustrated her roommates had been getting, and it was nice outside anyway. Late Spring was a wonderful time, aside from the horrid allergies and stinging insects.

"Come on then Bill. I just want to walk around to clear my head. This semester is getting super stressful." Katie stuffed her hands into her pockets.

"Never did any schooling myself. Born brilliant, read books, got more brilliant. It looks dull. All the lecturing and note taking and dealing with people knowing more than you and lording it over you." Bill smirked.

"Yeah, wouldn't know about that."

"Hey, at least you get a break over the Summer. That's how it works, yes?"

"Well yeah, but I'm not even getting a real break. I've gotta work on my honors thesis, and I'm starting an internship with one of the history professors. He researches cloning!"

"Ooh, now that's deliciously controversial! Anything I can do to help?" Bill threw a wide, toothy grin her way, "I still owe you for helping me out a while back. What can I do for you? Smite an enemy? Make you rich? Make you famous? Come on and throw me a bone, kid, I can't follow you around forever!" He gave an exasperated sigh.

"I don't want any of those things. Sure I'm stressed as all Hell now, but that's fine. I'll get over it and keep on working. I've gotta beef up that resume so graduate schools will fight over me and maybe even pay me to learn!" Katie smiled and looked around.

It was a fairly warm night, and the air smelled heavily of the pine trees that grew in abundance there. Crickets chirped loudly around them and the noise was calming. Katie felt surprisingly calm on a walk alone in the dark with a potentially murderous demon. She knew Bill _probably _wasn't going to hurt her, even with the evident frustration crossing his admittedly handsome face. She shook that last thought off and tried to relax.

Bill thought for a few minutes before he stopped walking.

"Alright kid. I can't spend your life following you around waiting for something to be important enough to pay my debt. I like you, kid, you're spunky and get to the point pretty quick," Bill huffed, "But I'm not tailing you for the next 50 years. Booooring!"

"I don't want you following me everywhere anyway. Jo and Shea are almost at their wits ends with you and your pranks."

"Not my fault they have no sense of humor. Turning your gecko into a dragon was hilarious!"

"You're the only one that thought so."

Bill snorted and rolled his eye. Maybe he would stick around a bit longer. He still had to figure out what to do from here, and the girl could prove useful, if not at least fun to mess with. Free room and food was pretty nice, and a couch to sleep on was better than cold, wet earth. The good food Katie and her roommates made was definitely a plus.

"Hey kid. I'll make a deal with you. I won't do anything _too _outrageous if you make me a really good dinner tomorrow. Something with lots of meat and potatoes and pasta!" Bill cackled, walking back toward the familiar apartment building.

"Hmm...fine." Katie shook his hand, eyes going wide at the blue flames that hugged their hands.

"Whoa! Can you teach me to do that?"

Bill paused and grinned.

"That will require a much different deal, but we can discuss that later. We should head inside." Bill held the door open and let the girl pass, following only after casting a thoughtful glance around. He had sensed something right as they were getting close to the building, and it worried him.

Out in the dark, a shadowed form watched with blinding white eyes. It stood tall and endlessly dark, branch-like antlers blending it into the thick foliage. The creature drummed its long, thin fingers against the bark of a tree. This was an interesting development; Cipher was attempting to cultivate a disciple. While not unusual for demons (seriously, they seem to do it all the damn time holy shit), it was out of Cipher's normal pattern. Perhaps this could be useful. The creature sunk into the ground, using the light of a battered old lantern to guide itself home to its own forest.


	4. Chapter 4

**Chapter Four: A Visit from an Old...Friend**

Bill woke with a jolt, sitting upright on the couch and looking around. It was the middle of the night; the living room was dark, the building was quiet, and everyone else was still asleep. Sleep was something Bill found he actually enjoyed; it was refreshing, and his human body needed it. It took the dream demon a long time to fall asleep; he required near perfect silence, a rarity in a college apartment building. It wasn't sound that had woken him up, however. It was a dream.

Bill didn't dream. It just wasn't something he wanted to get involved in. Other people's dreams, sure, fine, they were fun and impersonal. Things from his own subconscious were off limits. So when his sleeping mind had begun creating strange, dim swaths of color and texture, suffice it to say he was a little concerned. When one of those patterns solidified into a familiar blue square, he was startled awake.

Bill turned to look at the person he _knew _would be sitting in the armchair across from him; and there he was. The man was dressed in a blue suit, black hair carefully styled with a little black bowlder hat perched atop his head. His eyes glowed a baby blue, and his grin flashed dangerously sharp teeth. He was taller than Bill, long legs crossed elegantly and spider-like fingers knitted together in his lap. A blue umbrella rested across his lap as well, and he was the textbook picture of "too fucking smug for a guy sitting in a dark room like a creep".

"Coffee, Bill? I made some while you were sleeping." the man purred in a deep, calming voice.

"I'd rather not. I plan on returning to sleep once you leave me the fuck alone, Strange." Bill snapped back.

"Fine, more for me. So, how have you been? I've not seen you in a while, you never visit. We used to be so close. The best of pals." Tad Strange drank from a green coffee mug taken from the kitchen.

"We were never pals, you fucking square. What do you want?"

Tad frowned and set his mug aside, the amused air that had been around him gone immediately.

"Right to business, then. Unusual for you, but I appreciate a man who gets right to the point. You made yourself an enemy when you helped those two human kids out of the Unknown, Bill Cipher. They were marked to fuel the lantern. You know we aren't supposed to mess with anything in that realm."

Bill huffed and rolled his eye.

"Well you know me. Never been one for rules. Besides, a deal is a deal. They filled their half and I filled mine. They're alive and I got what I needed. So it's all over and done with, no harm no foul." He shrugged and settled back into his makeshift bed of blankets and pillows.

"Except the world doesn't work that way, Bill. He attacked you a while back, didn't he?" The silence he was answered with was all Tad needed. "Dammit, Bill, I can't always come behind you and pick up your messes! You just have to go fuck up everything and I have to clean up after you or everything turns to a steaming pile of shit."

"You don't _have _to do anything, Tad! I never asked for your help. Now fuck off and let me sleep. I've got a lot of work to do!" Bill snarled, eye glowing red in irritation.

"Yeah, I've seen. Cultivating a little lap dog to do your bidding. You couldn't get that boy to fall for it so now, several years later, instead of learning from your mistakes you're trying again. Well, good luck to you. Here," Tad tossed an envelope to him, "It's a letter addressed to your little lady from that Pine Tree kid. He's very adamant about her not trusting you." Tad chuckled.

"Yeah, that's why I'll be keeping this with me. Got any other gifts or is this it?"

"That's it. Just...be careful, Bill. This Beast is vengeful and won't be driven off by some clever riddles and a screaming head. He's not human, and he's not a demon, so your usual tricks won't work."

"I'll be fine. I suggest you worry about your own problems, Tad. I can handle myself."

Tad frowned thoughtfully at him, then simply sighed and nodded. With a loud snap of his fingers he was gone, the only trace left a heavy smell of cologne and the empty green mug. Bill grunted and rolled onto his side, happy to return to a thankfully dreamless sleep.


End file.
